Patent Document 1 discloses a conventional intermeshing type of kneading rotor. In the kneading rotor disclosed in Patent Document 1, the ratio 1/L between the length l of the long blade of the rotor and the length L of the rotor in the axial direction is specified as 0.6 or greater, and furthermore, the ratio a/L between the length a in the axial direction of the portion of the rotor between the end of the long blade and the end of the rotor in the axial direction, and the aforementioned length L is specified as 0.2 or lower. Therefore, it is possible to knead a material efficiently by means of the long blade. Furthermore, since the flow of material can be made to branch off from both ends of the long blade, kneading non-uniformities of the material are eliminated.
In a closed kneading machine, the material fluidity properties (distribution performance) and the material shearing properties (scattering performance) are both important factors. However, in a conventional kneading rotor, if the screw angle of the long blade is increased, then although the fluidity properties (distribution performance) are raised, the shearing properties (scattering performance) declines.    Patent Document 1: Japanese Patent No. 2803960